Revert "Perform CPU sampling by CPU sampling thread only iff processing thread is not running."

src/cpu-profiler.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 106 matching lines @@
   static TickSampleEventRecord* cast(void* value) {
     return reinterpret_cast<TickSampleEventRecord*>(value);
   }
 };
 
 
 // This class implements both the profile events processor thread and
 // methods called by event producers: VM and stack sampler threads.
 class ProfilerEventsProcessor : public Thread {
  public:
-  explicit ProfilerEventsProcessor(ProfileGenerator* generator,
-                                   Sampler* sampler,
-                                   int period_in_useconds);
+  explicit ProfilerEventsProcessor(ProfileGenerator* generator);
   virtual ~ProfilerEventsProcessor() {}
 
   // Thread control.
   virtual void Run();
   inline void Stop() { running_ = false; }
   INLINE(bool running()) { return running_; }
 
   // Events adding methods. Called by VM threads.
   void CallbackCreateEvent(Logger::LogEventsAndTags tag,
                            const char* prefix, String* name,
@@ skipping 11 matching lines @@
                        Address start, unsigned size);
   void CodeMoveEvent(Address from, Address to);
   void CodeDeleteEvent(Address from);
   void SharedFunctionInfoMoveEvent(Address from, Address to);
   void RegExpCodeCreateEvent(Logger::LogEventsAndTags tag,
                              const char* prefix, String* name,
                              Address start, unsigned size);
   // Puts current stack into tick sample events buffer.
   void AddCurrentStack();
 
-  // StartTickSampleEvent returns a pointer only if the ticks_buffer_ is empty,
-  // FinishTickSampleEvent marks the ticks_buffer_ as filled.
-  // Finish should be called only after successful Start (returning non-NULL
-  // pointer).
-  INLINE(TickSample* StartTickSampleEvent());
-  INLINE(void FinishTickSampleEvent());
+  // Tick sample events are filled directly in the buffer of the circular
+  // queue (because the structure is of fixed width, but usually not all
+  // stack frame entries are filled.) This method returns a pointer to the
+  // next record of the buffer.
+  INLINE(TickSample* TickSampleEvent());
 
  private:
   union CodeEventsContainer {
     CodeEventRecord generic;
 #define DECLARE_CLASS(ignore, type) type type##_;
     CODE_EVENTS_TYPE_LIST(DECLARE_CLASS)
 #undef DECLARE_TYPE
   };
 
   // Called from events processing thread (Run() method.)
   bool ProcessCodeEvent(unsigned* dequeue_order);
   bool ProcessTicks(unsigned dequeue_order);
-  void ProcessEventsQueue(int64_t stop_time, unsigned* dequeue_order);
 
   INLINE(static bool FilterOutCodeCreateEvent(Logger::LogEventsAndTags tag));
 
   ProfileGenerator* generator_;
-  Sampler* sampler_;
   bool running_;
-  // Sampling period in microseconds.
-  const int period_in_useconds_;
   UnboundQueue<CodeEventsContainer> events_buffer_;
-  TickSampleEventRecord ticks_buffer_;
-  bool ticks_buffer_is_empty_;
-  bool ticks_buffer_is_initialized_;
+  SamplingCircularQueue ticks_buffer_;
   UnboundQueue<TickSampleEventRecord> ticks_from_vm_buffer_;
   unsigned enqueue_order_;
 };
 
 } }  // namespace v8::internal
 
 
 #define PROFILE(isolate, Call)                                \
   LOG_CODE_EVENT(isolate, Call);                              \
   do {                                                        \
@@ skipping 18 matching lines @@
   static CpuProfile* StopProfiling(const char* title);
   static CpuProfile* StopProfiling(Object* security_token, String* title);
   static int GetProfilesCount();
   static CpuProfile* GetProfile(Object* security_token, int index);
   static CpuProfile* FindProfile(Object* security_token, unsigned uid);
   static void DeleteAllProfiles();
   static void DeleteProfile(CpuProfile* profile);
   static bool HasDetachedProfiles();
 
   // Invoked from stack sampler (thread or signal handler.)
-  // Finish should be called only after successful Start (returning non-NULL
-  // pointer).
-  static TickSample* StartTickSampleEvent(Isolate* isolate);
-  static void FinishTickSampleEvent(Isolate* isolate);
+  static TickSample* TickSampleEvent(Isolate* isolate);
 
   // Must be called via PROFILE macro, otherwise will crash when
   // profiling is not enabled.
   static void CallbackEvent(String* name, Address entry_point);
   static void CodeCreateEvent(Logger::LogEventsAndTags tag,
                               Code* code, const char* comment);
   static void CodeCreateEvent(Logger::LogEventsAndTags tag,
                               Code* code, String* name);
   static void CodeCreateEvent(Logger::LogEventsAndTags tag,
                               Code* code,
@@ skipping 42 matching lines @@
   Atomic32 is_profiling_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CpuProfiler);
 };
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_CPU_PROFILER_H_